Bacteria
are the most important prey for most species of amoeba. In
fact the very design of some very abundant genera such as Vannella,
Platyamoeba, Vexillifera and Acanthamoeba seem to
be dictated by the necessity to collect bacteria. The fan shape of
many amoeba may be a mechanism whereby the moving cell maximises the
contact with the substrate along which it moves so that the cell can
sweep up as many surface adherent bacteria as possible. This assumes of
course that this particular cell morphology is often on 2 dimensional
surfaces and this seems to be borne out. Vannella and Platyamoeba
are very abundant on macroalgae surfaces and (presumably) on the surface
of sand particles. Free-living amoeba are associated with biofilms in
dental units (Barbeau &
Buhler, 2001).